package com.msunsoft.support.mybatis;

import java.lang.reflect.Field;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;
import java.util.Map;
import java.util.Properties;

import javax.xml.bind.PropertyException;

import org.apache.commons.lang3.StringUtils;
import org.apache.ibatis.executor.ErrorContext;
import org.apache.ibatis.executor.ExecutorException;
import org.apache.ibatis.executor.statement.BaseStatementHandler;
import org.apache.ibatis.executor.statement.RoutingStatementHandler;
import org.apache.ibatis.executor.statement.StatementHandler;
import org.apache.ibatis.mapping.BoundSql;
import org.apache.ibatis.mapping.MappedStatement;
import org.apache.ibatis.mapping.ParameterMapping;
import org.apache.ibatis.mapping.ParameterMode;
import org.apache.ibatis.plugin.Interceptor;
import org.apache.ibatis.plugin.Intercepts;
import org.apache.ibatis.plugin.Invocation;
import org.apache.ibatis.plugin.Plugin;
import org.apache.ibatis.plugin.Signature;
import org.apache.ibatis.reflection.MetaObject;
import org.apache.ibatis.reflection.property.PropertyTokenizer;
import org.apache.ibatis.scripting.xmltags.ForEachSqlNode;
import org.apache.ibatis.session.Configuration;
import org.apache.ibatis.type.TypeHandler;
import org.apache.ibatis.type.TypeHandlerRegistry;

import com.msunsoft.common.Page;
import com.msunsoft.util.ReflectHelper;


@Intercepts({ @Signature(type = StatementHandler.class,method = "prepare",args = { Connection.class }) })
public class PagePlugin implements Interceptor {

    private static String dialect   = ""; // 数据库方言
    private static String pageSqlId = ""; // mapper.xml中需要拦截的ID(正则匹配)

    public Object intercept(Invocation ivk) throws Throwable{
        // TODO Auto-generated method stub
        if (ivk.getTarget () instanceof RoutingStatementHandler) {
            RoutingStatementHandler statementHandler = (RoutingStatementHandler) ivk.getTarget ();
            BaseStatementHandler delegate = (BaseStatementHandler) ReflectHelper.getValueByFieldName (statementHandler, "delegate");
            MappedStatement mappedStatement = (MappedStatement) ReflectHelper.getValueByFieldName (delegate, "mappedStatement");

            if (mappedStatement.getId ().matches (pageSqlId)) { // 拦截需要分页的SQL
                BoundSql boundSql = delegate.getBoundSql ();
                Object parameterObject = boundSql.getParameterObject ();// 分页SQL<select>中parameterType属性对应的实体参数，即Mapper接口中执行分页方法的参数,该参数不得为空

                if (parameterObject == null) {
                    throw new NullPointerException ("parameterObject尚未实例化！");
                } else {
                    Connection connection = (Connection) ivk.getArgs ()[0];
                    String sql = boundSql.getSql ();

                    String countSql = "select count(0) from (" + sql + ") tmp_count"; // 记录统计
                    PreparedStatement countStmt = connection.prepareStatement (countSql);
                    BoundSql countBS = new BoundSql (mappedStatement.getConfiguration (),countSql,boundSql.getParameterMappings (),parameterObject);
                    setParameters (countStmt, mappedStatement, countBS, parameterObject);
                    System.out.println ();
                    ResultSet rs = countStmt.executeQuery ();
                    System.out.println ("-----------------");
                    int count = 0;
                    if (rs.next ()) {
                        count = rs.getInt (1);
                    }

                    rs.close ();
                    countStmt.close ();
                    // System.out.println(count);
                    Page page = null;
                    if (parameterObject instanceof Page) { // 参数就是Page实体
                        page = (Page) parameterObject;
                        page.setEntityOrField (true); // 见com.flf.entity.Page.entityOrField 注释
                        page.setTotalResult (count);
                    } else if (parameterObject instanceof Map) { // 参数就是Map
                        Map pageMap = (Map) parameterObject;
                        page = (Page) pageMap.get ("page");
                        if (page == null) throw new NoSuchFieldException (parameterObject.getClass ().getName () + "不存在 page 属性!");
                        page.setEntityOrField (false); // 见com.flf.entity.Page.entityOrField 注释
                        page.setTotalResult (count);
                    } else { // 参数为某个实体，该实体拥有Page属性
                        Field pageField = ReflectHelper.getFieldByFieldName (parameterObject, "page");
                        if (pageField != null) {
                            page = (Page) ReflectHelper.getValueByFieldName (parameterObject, "page");
                            if (page == null) page = new Page ();
                            page.setEntityOrField (false); // 见com.flf.entity.Page.entityOrField 注释
                            page.setTotalResult (count);
                            ReflectHelper.setValueByFieldName (parameterObject, "page", page); // 通过反射，对实体对象设置分页对象
                        } else {
                            throw new NoSuchFieldException (parameterObject.getClass ().getName () + "不存在 page 属性!");
                        }
                    }
                    System.out.println ("==================ssssssssssssssssssssss" + sql);
                    String pageSql = generatePageSql (sql, page);
                    ReflectHelper.setValueByFieldName (boundSql, "sql", pageSql); // 将分页sql语句反射回BoundSql.
                }
            }
        }
        return ivk.proceed ();
    }

    /**
     * 对SQL参数(?)设值,参考org.apache.ibatis.executor.parameter.DefaultParameterHandler
     * 
     * @param ps
     * @param mappedStatement
     * @param boundSql
     * @param parameterObject
     * @throws SQLException
     */
    private void setParameters(PreparedStatement ps,MappedStatement mappedStatement,BoundSql boundSql,Object parameterObject) throws SQLException{
        ErrorContext.instance ().activity ("setting parameters").object (mappedStatement.getParameterMap ().getId ());
        List<ParameterMapping> parameterMappings = boundSql.getParameterMappings ();
        if (parameterMappings != null) {
            Configuration configuration = mappedStatement.getConfiguration ();
            TypeHandlerRegistry typeHandlerRegistry = configuration.getTypeHandlerRegistry ();
            MetaObject metaObject = parameterObject == null ? null : configuration.newMetaObject (parameterObject);
            for ( int i = 0 ; i < parameterMappings.size () ; i++ ) {
                ParameterMapping parameterMapping = parameterMappings.get (i);
                if (parameterMapping.getMode () != ParameterMode.OUT) {
                    Object value;
                    String propertyName = parameterMapping.getProperty ();
                    PropertyTokenizer prop = new PropertyTokenizer (propertyName);
                    if (parameterObject == null) {
                        value = null;
                    } else if (typeHandlerRegistry.hasTypeHandler (parameterObject.getClass ())) {
                        value = parameterObject;
                    } else if (boundSql.hasAdditionalParameter (propertyName)) {
                        value = boundSql.getAdditionalParameter (propertyName);
                    } else if (propertyName.startsWith (ForEachSqlNode.ITEM_PREFIX) && boundSql.hasAdditionalParameter (prop.getName ())) {
                        value = boundSql.getAdditionalParameter (prop.getName ());
                        if (value != null) {
                            value = configuration.newMetaObject (value).getValue (propertyName.substring (prop.getName ().length ()));
                        }
                    } else {
                        value = metaObject == null ? null : metaObject.getValue (propertyName);
                    }
                    TypeHandler typeHandler = parameterMapping.getTypeHandler ();
                    if (typeHandler == null) { throw new ExecutorException ("There was no TypeHandler found for parameter " + propertyName + " of statement " + mappedStatement.getId ()); }
                    typeHandler.setParameter (ps, i + 1, value, parameterMapping.getJdbcType ());
                }
            }
        }
    }

    /**
     * 根据数据库方言，生成特定的分页sql
     * 
     * @param sql
     * @param page
     * @return
     */
    private String generatePageSql(String sql,Page page){
        if (page != null && !StringUtils.isBlank (dialect)) {
            StringBuffer pageSql = new StringBuffer ();
            if ("mysql".equals (dialect)) {
                pageSql.append (sql);
                if (page.getSortName () != null && page.getSortOrder () != null) pageSql.append (" ORDER BY " + page.getSortName () + " " + page.getSortOrder ());
                pageSql.append (" limit " + page.getCurrentResult () + "," + page.getShowCount ());
            } else if ("oracle".equals (dialect)) {
                pageSql.append ("select * from (select tmp_tb.*,ROWNUM row_id from (");
                pageSql.append (sql);
                // xuchengli 2015年4月20日08:20:31 增加排序字段
                if (page.getSortName () != null && page.getSortName ().length () > 0 && page.getSortOrder () != null && page.getSortOrder ().length () > 0)
                    pageSql.append (" ORDER BY " + page.getSortName () + " " + page.getSortOrder ());
                pageSql.append (")  tmp_tb where ROWNUM<=");
                pageSql.append (page.getCurrentResult () + page.getShowCount ());
                pageSql.append (") where row_id>");
                pageSql.append (page.getCurrentResult ());
            }
            System.out.println (pageSql.toString () + "==========");
            return pageSql.toString ();
        } else {
            return sql;
        }
    }

    public Object plugin(Object arg0){
        // TODO Auto-generated method stub
        return Plugin.wrap (arg0, this);
    }

    public void setProperties(Properties p){
        dialect = p.getProperty ("dialect");
        if (StringUtils.isBlank (dialect)) {
            try {
                throw new PropertyException ("dialect property is not found!");
            } catch (PropertyException e) {
                // TODO Auto-generated catch block
                e.printStackTrace ();
            }
        }
        pageSqlId = p.getProperty ("pageSqlId");
        if (StringUtils.isBlank (pageSqlId)) {
            try {
                throw new PropertyException ("pageSqlId property is not found!");
            } catch (PropertyException e) {
                // TODO Auto-generated catch block
                e.printStackTrace ();
            }
        }
    }

}
